Although the meanings of the following acronyms are well understood by skilled artisans, the following list is deemed to assist in a better understanding of the invention:
3GPP third generation partnership project
AAA authentication, authorization, and accounting
AP access point
CCF charging control function
CSCF call state control function
EIR equipment identity register
GGSN gateway GPRS support node
GMSC gateway MSC
GPRS general packet radio system
GSM global system for mobile communication
HLR home location register
HSS home subscriber server
IP internet protocol
IWMSC interworking MSC for SMS
MMS multi-media services
MS mobile station
MSC mobile switching station
PDG packet data gateway
PHY physical layer
PDA personal digital assistant
SC service center
SIM subscriber identity module
SMS short messaging service
TCP transmission control protocol
UMTS universal mobile telecommunications system
VoIP voice over internet protocol
WAG wireless application gateway
WAT wireless access technology
WLAN wireless local area network
WTRU wireless transmit/receive unit
The trend in the wireless industry is to increasingly support wireless transmit/receive units (WTRUs) that support multiple Wireless Access Technologies (WATs) in heterogeneous networks. Network interworking introduces the possibility of several WATs (e.g., several different types of wireless local area networks) such 802.11a, 802.11b, 802.11g, etc. being connected to a cellular type network (e.g., a Universal Mobile Telecommunications System (UMTS) network). Further, using subscriber identity module (SIM) technology, users may switch their 802.11b card to an 802.11a card, for example, or any other type of multi-mode card using their SIM to access the network while the network is not totally aware of the WAT supported at the WTRU level. Additionally, users may use their 802.11 cards, for example, in different types of WTRUs, such as when they obtain a new laptop or personal digital assistant (PDA), for example.
In light of the above, it is desirable to efficiently handle various types of wireless services across multiple WATs for WTRUs that may operate in cellular and WLAN type networks.